Lithium/oxygen, or lithium/air secondary batteries, has been explored as electrochemical cells. The theoretical specific energy of a lithium air battery is much higher than conventional lithium ion systems, estimated at over 40 MJ/kg, rendering it potentially useful in a wide number of settings. However, the primary product of the discharged battery, Li2O2, is insoluble in common electrolyte solvents. As such, lithium air systems are not suitable as secondary (i.e., rechargeable) systems. Moreover, the required presence of oxygen in the system presents the potential for unintended combustion.
There remains a need for improved secondary metal-gas batteries with high energy and robust rechargeability.